Unmanned Systems Technology Dec/Jan 2020 | Phoenix UAS | Sonar focus | Construction insight | InterGeo 2019 | Supacat ATMP | Adelan fuel cell | Oregon tour | DSEI 2019 | Copperstone Helix | Power management focus

64 Dossier | Adelan solid oxide fuel cell temperatures of SOFCs enable them to use some form of catalytic breakdown reaction to produce hydrogen from the fuel to the cell – typically catalytic partial oxidisation (CPOx). This catalytic system sits between the fuel supply and the cell stack, and is what gives SOFCs their multi-fuel capability. Dr Kendall also saw notable problems with the planar (or ‘flat plate’) designs that many SOFCs are based around. “The materials have to be sealed – you’d have plates of ceramic forming the anode, electrolyte and cathode, with sealant all around them to make them gas-tight. And all the materials and sealants needed matching thermal expansion coefficients,” she says. It is deeply challenging to achieve the same thermal expansion and contraction rates across all of these materials, and thus flat-plate SOFCs are highly prone to leaks and contaminants, often restricting their lifespans. The design of the pipe – or ‘micro- tube’, as Adelan calls it, to differentiate it from another design that uses tubular fuel cells of 10-15 cm diameter – avoids this problem. With most of the heat generation occurring in the middle of the micro-tubes, rubber tubing can be attached around the cold ends on either side, with one tube at one end of the December/January 2020 | Unmanned Systems Technology Adelan is based in Birmingham, England, and was formed in 1996 to continue the development and commercialisation of Dr Michaela Kendall’s patented microtubular solid oxide fuel cell (mSOFC) design. The company has close ties with the University of Birmingham, having been based in the university’s science park between 1997 and 2001, and continues to collaborate with all three universities in Birmingham for fuel cell research and tests of its mSOFC projects. The mSOFC is the brainchild of Dr Kendall, who studied environmental science and technology at Middlesex University from 1989. Having learned about a range of renewable energy sources, she turned towards fuel cells – after being inspired by her father’s own research in that area – for her thesis in 1993. As she recounts, “I looked at the SOFC designs of one of the most dominant companies in the field. Their cells had a ‘test tube’ shape to them, with the anode, electrolyte and cathode structured as long, thin, U-shapes; one end was blocked. The other SOFC designs were all flat plates. “Considering the thermal and fluid dynamics involved, it struck me as odd that they didn’t simply use a pipe shape, with openings on both sides. Because gas goes down a pipe.” Dr Kendall soon moved towards developing early prototypes of pipe-like (or microtubular) SOFCs. “The initial mSOFCs were a bit rough, as they’d been made quickly and to very general specifications in terms of length and diameter. From that first batch I made in September 1992, however, we started experimenting with and refining this new form of SOFC technology. “I published the test results the following year. As far as I know, tubular SOFCs had been theorised about but never produced and tested.” Seeing value in the design, Dr Kendall’s father applied for a patent on it in 1994, and in 1996 Adelan was founded to pursue its own manufacturing and r&d of mSOFCs. Since then, there has been a continual stream of global interest in pushing Adelan’s technology towards the market. Between 1998 and 2001, Adelan worked on its first commercial project for a company in the US, and from about 2003 onwards the company began almost routinely manufacturing and selling its SOFC technology, mostly in Europe. It has since developed mSOFC power systems for small stationary operations, electric cars, unmanned vehicles and other applications. History of the mSOFC Propane (red bottle, right) has been selected from time to time as the fuel of choice in the mSOFC module (left) for its energy-to-weight ratio, which is higher than that of hydrogen